The DocBook DTD defines structural and content-based SGML markup for computer documentation, with a primary emphasis on software documentation and related classes of technical documents. Its main high-level hierarchical structures are for books, reference entries (for example, ``man pages''), and articles. It is maintained by the Davenport Group (about which see the Davenport archive at http://www.ora.com/davenport/ or ftp://ftp.ora.com/pub/davenport/). This package contains DocBook XML V4.1.2, released 27 Aug 2000. Some documentation for DocBook is available in ASCII and PDF at http://www.freebsd.org/~wosch/docbook/